A typical narrow-aisle articulated forklift truck comprises front and rear chassis sections each having a pair of wheels on a respective common axis. The rear wheels are driven, while the front wheels are non-driven. The chassis sections are pivoted together about a vertical axis so that the front chassis section can be turned at an angle at or approaching 90° relative to the rear chassis section to allow the truck to insert loads into, and remove loads from, the face of the aisle, i.e. normal to the length of the aisle.
Clearly, as the steering angle increases the inner rear wheel, i.e. the wheel on the inside of the path taken by the truck, will turn more slowly than the outer rear wheel, and in fact may stop altogether or reverse if the axis of the front wheels coincides with or lies inside the ground contact point of the inner rear wheel at large steering angles. In conventional narrow-aisle articulated forklift trucks this leads to tyre wear and difficulties in manoeuvring and controlling the truck. At large steering angles, too, the rear driving wheels will tend to drive the forklift straight ahead (this is known as “dozing on”), with the front wheels skidding sideways.
It is an object of this invention to provide a construction of forklift truck in which this problem is avoided or mitigated.